Tube feeder



FIG. 1 is a front elevational view of a tube feeder showing our new design;

FIG. 2 is a right side elevational view thereof; and,

FIG. 3 is a top plan view thereof.

The broken lines shown in all views are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a tube feeder, as shown and described. 